Laborious coating a thing of the past

The new cordless (landline) telephones Gigaset S440 and S445 from Siemens mobile allow you to enjoy the convenience of modern cellphones at home too. Their elegant silvery design has been made possible by Bayfol

The faceplate of the handsets and the front part of the base stations are made from colored ABS film printed with a matte coating. By using this film, the components are given their final exterior design immediately, thus eliminating the time-consuming coating procedure involved in producing the finished components – particularly the base stations – in previous models.

“This has huge logistical benefits for Siemens, while also simplifying the production process. Coating prefabricated components is very complex in terms of plant technology. The process requires extensive occupational safety measures and frequently results in a higher number of rejects,” explains Roland Künzel, films expert at Bayer MaterialScience.

The ABS film, which has a thickness of 250 micrometers, is given its matte coating by the Seelbach-based company Albea Kunststofftechnik GmbH in a reel-to-reel screen printing process. It is then thermoformed and punched. At Siemens, the resulting insert components are then back-injected with an ABS thermoplastic using the film insert molding technique (FIM).

“The fronts of the base stations in particular are proof that FIM technology with colored plastic films also has tangible benefits and produces very high-quality surfaces in the manufacture of larger casing components for telecommunications devices,” says Künzel. The design scope and choice of color that this offers is huge. An alternative method for producing these components is injection molding with colored thermoplastics. However, this nearly always results in unattractive flow lines, especially when a metallic look is required.